[Blood levels of phenytoin. Pharmacokinetics and individualization of dosages in controlled children with crises and with persistence of crises].
The pharmacokinetics of phenytoin was evaluated using the Michaelis-Menten technique in children with seizures seen at the Outpatient Ward, in order to adjust their medication dosages based on a clinical-pharmacological relation. The children were divided into two groups: Group A (controlled seizures) and group B (persistent seizures). Each group of children were orally given 7 mg/kg of phenytoin. Their serum levels were measured using enzymatic immunoassay at one, two, four, eight and 12 hours after taking the medication. There was a significant correlation (P less than 0.05) between the average saturation constant (Km) and the maximum speed (Vmax) with age and the doses administered in group A, which showed a lesser metabolic capacity than group B. There was also a significant correlation (P less than 0.05) when predicting the levels in each group. Clinically, the patients group A were controlled while those in group B witnessed a lesser frequency and intensity of the seizures in six patients, two were controlled and two others remained the same. The data shows a clinical-pharmacological correlation in children difficult to control, and improves the dosaging criteria used each individuals needs.
García-Márquez
F
F
Unidad de Farmacología Clínica, Hospital General de México, D.F.
Rodríguez-Blancas
M C
MC
Juárez-Olguín
H
H
Díaz-López
B
B
Ruiz-Chávez
J
J
D000293:Adolescent; D002648:Child; D004827:Epilepsy / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D010672:Phenytoin / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics*
D010672:Phenytoin
Niveles séricos de fenitoína. Farmacocinética e individualización de dosis en niños con crisis controlados y con persistencia de las crisis.